Integrated three dimensional display and method of recording identification information

ABSTRACT

An integrated three-dimensional display includes a recording surface which includes a calculated element region in which phase components of light from light converging points of a holographic reconstructed image are calculated, and a phase angle recorded area for recording a phase angle calculated based on the phase components. The phase angle recorded area includes a plurality of monochromatic regions having a uneven structure surface. The phase angle is recorded in an overlap area in which the calculated element region and the phase angle recorded area overlap each other. Light converges on the light converging points at specific distances from the recording surface, the specific distances being determined for the respective light converging points even when light reflected from the plurality of monochromatic regions converges.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a continuation application filed under 35 U.S.C. §111(a) claiming the benefit under 35 U.S.C. §§ 120 and 365(c) ofInternational Patent Application No. PCT/JP2019/040513, filed on Oct.15, 2019, which is based upon and claims the benefit of priority toJapanese Patent Application No. 2018-195365, filed on Oct. 16, 2018, thedisclosures of which are incorporated herein by reference in theirentireties.

TECHNICAL FIELD

Embodiments of the present invention relate to integratedthree-dimensional displays in which, for example, phase components ofspatial information calculated by a computer are recorded to apply to ahologram, and also relate to methods of recording identificationinformation.

BACKGROUND

As disclosed in the following prior art documents, there have beenrecently disclosed computer-generated holograms controlled byinterference of light calculated by a computer: (PTL 1) JP 4525151 B2;(PTL 2) WO 2018/097238 A1; (PTL 3) WO 2016/167173 A1.

The techniques disclosed in the above patent documents may be appliedto, for example, securities, card media, and authentication media. Forexample, PTL 1 discloses the technique for displaying a full-colorthree-dimensional image by forming a uneven structure having differentperiodicities for each wavelength.

Further, PTLs 2 and 3 disclose the technique called a Lippmann hologram,which is a technique for displaying a full-color three-dimensional imageby performing multiple recordings of images having different colorcomponents for each wavelength on a photosensitive material by using alaser light source.

SUMMARY OF THE INVENTION

However, the technique disclosed in PTL 1 does not consider the parallaxin the vertical direction, and is effective only when the parallax is inthe horizontal direction. Accordingly, the stereoscopic effect isachieved only in the horizontal direction. In addition, color shiftoccurs in the vertical direction, which causes iridescence.

This iridescent shift is a typical effect that occurs to most hologramscurrently commonly used, and leads to commoditization.

Further, Lippmann hologram described in PTLs 2 and 3, which canreconstruct a full-color three-dimensional image, can be usuallyproduced by a known method using an RGB three-color laser and aphotosensitive material.

However, the photosensitive materials are expensive compared withembossing holograms that use a general UV-curable resin. Further,Lippmann holograms using an RGB three-color laser require more cycletime than embossing holograms, and are not suitable for mass production.

In addition, when machine-readable codes are added to the photosensitivematerial, each machine-readable code needs to be individually producedand recorded on the photosensitive material, which is inconvenient.

Embodiments of the present invention have been made in view of the abovecircumstances, and aim to provide integrated three-dimensional displays,which provide three-dimensional images that can be reconstructed infull-color without causing iridescence and is suitable for massproduction, in combination with a machine-readable code, and providemethods of recording identification information.

According to a first aspect of the present invention, an integratedthree-dimensional display includes a recording surface on whichinformation for reconstructing a hologram is recorded, the recordingsurface includes a calculated element region in which phase componentsof light from light converging points of a holographic reconstructedimage are calculated, the calculated element region being defined byone-to-one correspondence to the light converging points, and a phaseangle recorded area for recording a phase angle calculated based on thephase components. The phase angle recorded area includes a plurality ofmonochromatic regions having a uneven structure surface in whichprotrusion structures and recess structures are alternately arranged ata pitch that is an integral multiple of a predetermined resolution.Further, the phase angle is recorded in an overlap area in which thecalculated element region and the phase angle recorded area overlap eachother. Light converges on the light converging points at specificdistances from the recording surface, the specific distances beingdetermined for the respective light converging points even when lightreflected from the plurality of monochromatic regions converges.

According to a second aspect of the present invention, in the integratedthree-dimensional display of the first aspect of the present invention,two-dimensional information is provided on the recording surface tooverlap at least part of the reconstructed image in a depth direction ofthe recording surface.

According to a third aspect of the present invention, in the integratedthree-dimensional display of the second aspect of the present invention,the two-dimensional information is provided on the recording surface anddoes not cover an entire surface of the phase angle recorded area.

According to a fourth aspect of the present invention, in the integratedthree-dimensional display of the second aspect of the present invention,at least one of the reconstructed image and the two-dimensionalinformation includes personal identification information.

According to a fifth aspect of the present invention, in the integratedthree-dimensional display of the second aspect of the present invention,at least one of a shape of the monochromatic regions on the recordingsurface, a shape of the two-dimensional information, and a shape of thereconstructed image represents a character or a mark.

According to a sixth aspect of the present invention, in the integratedthree-dimensional display of the second aspect of the present invention,at least one of a shape of the monochromatic regions on the recordingsurface, a shape of the two-dimensional information, and a shape of thereconstructed image represents a machine-readable code.

According to a seventh aspect of the present invention, in theintegrated three-dimensional display of the first aspect of the presentinvention, the recording surface further includes a phase anglenon-recorded area that does not record a phase angle, and the phaseangle non-recorded area in the calculated element region has a mirrorsurface.

According to an eighth aspect of the present invention, in theintegrated three-dimensional display of the first aspect of the presentinvention, the recording surface further includes a phase anglenon-recorded area that does not record a phase angle, and the phaseangle non-recorded area in the calculated element region recordsinformation other than the phase angle.

According to a ninth aspect of the present invention, in the integratedthree-dimensional display of the eighth aspect of the present invention,the information other than the phase angle is information including atleast one of scattering, reflection, and diffraction of light.

According to a tenth aspect of the present invention, in the integratedthree-dimensional display of the first aspect of the present invention,the phase angle is calculated as φ according to the following formula.

$\begin{matrix}{{{W( {{kx},{ky}} )} = {\sum\limits_{n = 0}^{N\;\max}{\sum\limits_{{ky} = {Y\;\min}}^{Y\;\max}{\sum\limits_{{kx} = {X\;\min}}^{X\;\max}{{amp} \cdot {\exp( {i\;\phi} )}}}}}}{\phi = {\frac{\pi}{\lambda \cdot {O_{n}(z)}}\{ {( {{O_{n}(x)} - {kx}} )^{2} + ( {{O_{n}(y)} - {ky}} )^{2}} \}}}} & \lbrack {{Math}.\mspace{11mu} 1} \rbrack\end{matrix}$

In the formula, (kx, ky) are coordinates of a pixel that constitute themonochromatic regions, W (kx, ky) represents the phase components of thecoordinates (kx, ky), n is an index of the plurality of the lightconverging points Sn (n=0 to Nmax), amp is an amplitude of light at thelight converging points Sn, i is an imaginary number, λ is a wavelengthof light in reconstruction of the reconstructed image, On (x, y, z)represents coordinates of the light converging points Sn, and Xmin,Xmax, Ymin, and Ymax are coordinates indicating a range of thecalculated element region defined for the respective light convergingpoints.

According to an eleventh aspect of the present invention, in theintegrated three-dimensional display of the first aspect of the presentinvention, the number of types of the monochromatic regions correspondsto a number of colors required to reconstruct the hologram, a color ofreflected light reflected from the monochromatic regions is one of thecolors required to reconstruct the hologram, a depth of the recessstructures in each of the monochromatic regions is determined dependingon the color of reflected light, and the determined depth of the recessstructures is recorded in the monochromatic regions in the overlap areainstead of the phase angle being recorded in the overlap area.

According to a twelfth aspect of the present invention, in theintegrated three-dimensional display of the first aspect of the presentinvention, a void is embedded in the overlap area instead of the phaseangle being recorded in the overlap area, the void having a void sizemodulated according to the phase angle.

According to a thirteenth aspect of the present invention, in theintegrated three-dimensional display of the first aspect of the presentinvention, the integrated three-dimensional display includes a pluralityof the calculated element regions, wherein, among the plurality ofcalculated element regions, the respective calculated element regionspositioned on the recording surface without overlapping other calculatedelement regions are colored in different colors from other calculatedelement regions.

According to a fourteenth aspect of the present invention, in theintegrated three-dimensional display of the first aspect of the presentinvention, the recording surface includes a metallic reflective layer.

According to a fifteenth aspect of the present invention, in theintegrated three-dimensional display of the first aspect of the presentinvention, the integrated three-dimensional display is attached to anobject.

According to a sixteenth aspect of the present invention, in theintegrated three-dimensional display of the first aspect of the presentinvention, a distance between the recording surface and each of thelight converging points is in a range of 0.5 (mm) or more and 50 (mm) orless, and the integrated three-dimensional display is designed to beobserved in an angular range of 0(°) or more and 70(°) or less relativeto a direction normal to the recording surface.

According to a seventeenth aspect of the present invention, a method ofrecording identification information includes demetallizing the metallicreflective layer corresponding to identification information to therebyrecord the identification information on the integratedthree-dimensional display of the fourteenth aspect.

According to an eighteenth aspect the present invention, in the methodof recording identification information of the seventeenth aspect of thepresent invention, the identification information is a machine-readablecode, and the demetallizing includes demetallizing 30(%) or more and70(%) or less of a metal of a portion of the metallic reflective layerwhich is desired to be non-reflective in order to produce themachine-readable code by combining reflection and non-reflection.

According to a nineteenth aspect of the present invention, a method ofrecording identification information includes providing a print layer onthe recording surface; and recording identification information on theprint layer to thereby record the identification information on theintegrated three-dimensional display of the first aspect.

According to the integrated three-dimensional display of the firstaspect of the present invention, in which the calculated element regionis provided, it is possible to reduce computation time by a computer,reduce the noise of spatial information, and obtain a clear hologram.

In the calculation, in particular, the phase angle can be calculated andrecorded. Such a phase hologram can modulate only the phase componentsof light while achieving high diffraction efficiency. Thus, light can becontrolled while the brightness of light being kept high.

Further, computation time by a computer can be further reduced bylimiting the phase angle recorded area for recording the phase anglewithin the calculated element region. In addition, the percentage oflight illuminating the integrated three-dimensional display can also becontrolled.

Further, when a portion of the calculated element region other than thephase angle recorded area is defined as a phase angle non-recorded area,the reconstructed image reconstructed at the light converging points canhave a brightness lower than that in a case where no phase anglenon-recorded area is provided by the amount represented by (phase anglerecorded area)/(phase angle recorded area+phase angle non-recordedarea). Thus, the brightness of reflected light can be controlled.

Moreover, the three-dimensional reconstructed image can be reconstructedonly when the phase angle recorded area is illuminated with light. Thatis, the larger the phase angle recorded area, the brighter thereconstructed image, and the smaller the phase angle recorded area, thedarker the reconstructed image. However, although capable ofreconstructing only a dark reconstructed image, the phase anglenon-recorded area can be used as another optical element.

Furthermore, when the phase angle recorded area being composed of one ora plurality of monochromatic regions, a monochromatic or color image canbe three-dimensionally reconstructed.

According to the integrated three-dimensional display of the secondaspect of the present invention, in which the two-dimensionalinformation is provided on the recording surface to overlap at leastpart of the reconstructed image in a depth direction of the recordingsurface, anti-counterfeiting properties can be greatly enhanced.

If a reconstructed image and two-dimensional information are simplyprovided and separated from each other on the recording surface,two-dimensional information can be counterfeited by changing only thegenuine original two-dimensional information. In this case, the genuinereconstructed image can be easily combined with counterfeitedtwo-dimensional information, increasing a risk of counterfeiting beingeasily performed. Accordingly, anti-counterfeiting properties arelowered. Further, if a three-dimensional reconstructed image andtwo-dimensional information are separately provided in two layers, oneof the layers which includes genuine two-dimensional information can beeasily replaced with a layer having counterfeited two-dimensionalinformation, which leads to a risk of counterfeiting being easilyperformed. Accordingly, anti-counterfeiting properties are lowered.However, according to the integrated three-dimensional display of thisaspect of the invention, these problems can be solved.

According to the integrated three-dimensional display of the thirdaspect of the present invention, the two-dimensional information isprovided on the recording surface and does not cover an entire surfaceof the phase angle recorded area. If the entire surface of the phaseangle recorded area which corresponds to one light converging point iscovered with two-dimensional information, a light converging point to bereconstructed from the phase angle recorded area will not appear.However, according to the integrated three-dimensional display of thisaspect of the invention, since the two-dimensional information isprovided not to cover the entire surface of the phase angle recordedarea, the light converging point to be reconstructed from the phaseangle recorded area can be prevented from disappearing.

According to the integrated three-dimensional display of the fourthaspect of the present invention, at least one of the reconstructed imageand the two-dimensional information can be used as personalidentification information.

According to the integrated three-dimensional display of the fifthaspect of the present invention, a dynamic three-dimensionalreconstructed image and a static two-dimensional information such as acharacter or a mark can be displayed in combination. Accordingly,anti-counterfeiting properties of the two-dimensional information can beenhanced.

According to the integrated three-dimensional display of the sixthaspect of the present invention, at least one of a shape of themonochromatic regions on the recording surface, a shape of thetwo-dimensional information, and a shape of the reconstructed imagerepresents a machine-readable code. Accordingly, a variable code havingenhanced anti-counterfeiting properties can be provided. Themachine-readable code may be a two-dimensional code or a one-dimensionalcode. The machine-readable code may be a QR code (registered trademark),a barcode, a data matrix, or the like.

According to the integrated three-dimensional display of the seventhaspect of the present invention, the phase angle non-recorded area inthe calculated element region on the recording surface can have a mirrorsurface.

According to the integrated three-dimensional display of the eighthaspect of the present invention, information other than a phase angle isrecorded in the phase angle non-recorded area in the calculated elementregion. Accordingly, information other than the phase components oflight of the three-dimensional reconstructed image can be controlled bythe phase angle non-recorded area.

According to the integrated three-dimensional display of the ninthaspect of the present invention, information other than a phase angle isinformation including at least one of scattering, reflection, anddiffraction of light. Accordingly, various types of light can becontrolled by using different types of light effects to thereby achievea complicated visual effect.

According to the integrated three-dimensional display of the tenthaspect of the present invention, a phase angle of coordinates of a pixelthat constitutes the monochromatic regions can be specificallycalculated according to the following formula.

$\begin{matrix}{{{W( {{kx},{ky}} )} = {\sum\limits_{n = 0}^{N\;\max}{\sum\limits_{{ky} = {Y\;\min}}^{Y\;\max}{\sum\limits_{{kx} = {X\;\min}}^{X\;\max}{{amp} \cdot {\exp( {i\;\phi} )}}}}}}{\phi = {\frac{\pi}{\lambda \cdot {O_{n}(z)}}\{ {( {{O_{n}(x)} - {kx}} )^{2} + ( {{O_{n}(y)} - {ky}} )^{2}} \}}}} & \lbrack {{Math}.\mspace{11mu} 2} \rbrack\end{matrix}$

According to the integrated three-dimensional display of the eleventhaspect of the present invention, the depth of the recess structures ofthe monochromatic region according to the phase angle, instead of thephase angle, can be recorded in the overlap area.

According to the integrated three-dimensional display of the twelfthaspect of the present invention, a void having a void size modulatedaccording to the phase angle can be embedded in the overlap area insteadof the phase angle being recorded in the overlap area.

According to the integrated three-dimensional display of the thirteenthaspect of the present invention, the respective calculated elementregions positioned on the recording surface without overlapping othercalculated element regions can be colored in different colors to therebyreconstruct a full-color three-dimensional reconstructed image.

According to the integrated three-dimensional display of the fourteenthaspect of the present invention, the recording surface includes ametallic reflective layer. Accordingly, the reflection efficiency oflight can be improved so that a bright reconstructed image can bereconstructed due to the reflected light.

According to the integrated three-dimensional display of the fifteenthaspect of the present invention, the integrated three-dimensionaldisplay can be attached to an object.

According to the integrated three-dimensional display of the sixteenthaspect of the present invention, although the reconstructed image may beblurred and not clearly visible depending on the size and number ofillumination sources such as fluorescent lamps in a typical officeenvironment or the like, the reconstructed image may be clearly visiblewhen illuminated with an LED, which is a point light source, or a lightsource of a smartphone or a cash register reader.

According to the method of recording identification information of theseventeenth aspect of the present invention, a portion of the metallicreflective layer which is desired to be non-reflective can bedemetallized by using a laser to record identification information.

According to the method of recording identification information of theeighteenth aspect of the present invention, a portion of the metallicreflective layer which is desired to be non-reflective can bedemetallized to record two-dimensional information. As thedemetallization amount increases, the contrast of the two-dimensionalinformation increases. This facilitates recognition of thetwo-dimensional information and increases the recognition rate per unittime, but decreases the brightness of the three-dimensionalreconstructed image. In contrast, as the demetallization amountdecreases, the three-dimensional reconstructed image has an increasedbrightness. However, the contrast of the machine-readabletwo-dimensional information decreases, and the recognition ratedecreases accordingly. According to the method of recordingidentification information of the eighteenth aspect of the presentinvention, 30(%) or more and 70(%) or less of a metal of a portion ofthe metallic reflective layer which is desired to be non-reflective canbe demetallized to achieve both easily recognizable two-dimensionalinformation and a bright reconstructed image.

According to the method of recording identification information of thenineteenth aspect of the present invention, a print layer can beprovided on the recording surface, and identification information can berecorded on the print layer. Accordingly, the phase angle recorded areaon the recording surface can be partially shielded, and the shieldedregion can be effectively used for recording two-dimensionalinformation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual diagram illustrating an integratedthree-dimensional display to which a method of recording identificationinformation according to an embodiment of the present invention isapplied.

FIG. 2 is a cross-sectional view illustrating a portion of an overlaparea in which a depth of a pixel according to a phase angle is recorded.

FIG. 3 is a front view of a reconstructed image produced by anintegrated three-dimensional display which includes an overlap areahaving an example configuration shown in FIG. 2.

FIG. 4 is a conceptual diagram illustrating a principle of full-colordisplay achieved by an integrated three-dimensional display according toan embodiment of the present invention.

FIG. 5A is a conceptual diagram illustrating an example arrangement of amonochromatic region that causes a light converging point to emit redlight.

FIG. 5B is a conceptual diagram illustrating an example arrangement of amonochromatic region that causes a light converging point to emit bluelight.

FIG. 5C is a conceptual diagram illustrating an example arrangement of amonochromatic region that causes a light converging point to emit violetlight.

FIG. 6 is a conceptual diagram illustrating an example arrangement of acolor conversion region in which RGBs are repeatedly arranged in avertical direction.

FIG. 7 is a conceptual diagram illustrating an example arrangement oftwo arrays of color conversion regions in which RGBs are repeatedlyarranged in a vertical direction.

FIG. 8 is a conceptual diagram illustrating an example arrangement of acolor conversion region in which only Gs are arranged in a verticaldirection.

FIG. 9 is a conceptual diagram illustrating an example arrangement of acolor conversion region in which R, B, and G are randomly arranged in avertical direction.

FIG. 10 is a conceptual diagram illustrating an example arrangement of acolor conversion region in which a plurality of pixel patterns arearranged.

FIG. 11 is a conceptual diagram illustrating an integratedthree-dimensional display having six types of monochromatic regions forreflected light of six wavelengths.

FIG. 12 is a conceptual diagram illustrating that different colors aredisplayed depending on the viewing position.

FIG. 13 is a conceptual diagram illustrating that two-dimensionalinformation having a shape representing a mark is applied to anintegrated three-dimensional display.

FIGS. 14A (a) and (b) are a cross-sectional view and a plan viewillustrating an example positional relationship between two-dimensionalinformation and three-dimensionally distributed light converging points,which do not overlap each other in the xy plane.

FIGS. 14B (a) and (b) are a cross-sectional view and a plan viewillustrating an example positional relationship between two-dimensionalinformation and three-dimensionally distributed light converging points,which overlap each other in the xy plane.

FIG. 15A is a conceptual diagram illustrating a positional relationshipbetween an overlap area and two-dimensional information on a recordingsurface (the overlap area is partially covered with the two-dimensionalinformation).

FIG. 15B is a conceptual diagram illustrating a positional relationshipbetween an overlap area and two-dimensional information on a recordingsurface (the overlap area is entirely covered with the two-dimensionalinformation).

FIGS. 16A (a) and (b) are a cross-sectional view and a plan viewillustrating an embodiment of an authentication medium in whichtwo-dimensional information (marks) and light converging points arelocated overlapping each other in the xy plane.

FIGS. 16B (a) and (b) are a cross-sectional view and a plan viewillustrating an embodiment of an authentication medium in whichtwo-dimensional information (a two-dimensional barcode) and lightconverging points are located overlapping each other in the xy plane.

FIGS. 17A (a) and (b) are a cross-sectional view and a plan viewillustrating an embodiment of an authentication medium having a markrepresented by a planar shape of a monochromatic region.

FIGS. 17B (a) and (b) are a cross-sectional view and a plan viewillustrating an embodiment of an authentication medium having a mark anda two-dimensional barcode represented by a planar shape of amonochromatic region.

FIG. 18A is a conceptual diagram illustrating that a three-dimensionalimage is reconstructed across a plurality of monochromatic regionshaving different reconstructed colors (when a viewing direction isobliquely directed from the right).

FIG. 18B is a conceptual diagram illustrating that a three-dimensionalimage is reconstructed across a plurality of monochromatic regionshaving different reconstructed colors (when a viewing direction isperpendicular to the surface).

FIG. 18C is a conceptual diagram illustrating that a three-dimensionalimage is reconstructed across a plurality of monochromatic regionshaving different reconstructed colors (when a viewing direction isobliquely directed from the left).

FIG. 19A is a cross-sectional view of an example of an integratedthree-dimensional display according to an embodiment of the presentinvention, illustrating an example method of changing a reflectionspectrum by demetallization (before demetallization).

FIG. 19B is a cross-sectional view of an example of an integratedthree-dimensional display according to an embodiment of the presentinvention, illustrating an example method of changing a reflectionspectrum by demetallization (after demetallization).

FIG. 20A is a conceptual diagram illustrating that inspection lightemitted from an authentication device is reflected by a reflectivelayer.

FIG. 20B is a conceptual diagram illustrating that inspection lightemitted from an authentication device is transmitted through ademetallized section.

FIG. 21A is a cross-sectional view of one embodiment of an integratedthree-dimensional display according to an embodiment of the presentinvention, illustrating a method of changing a reflection spectrum byproviding a print layer (monochromatic region configuration).

FIG. 21B is a cross-sectional view of one embodiment of an integratedthree-dimensional display according to an embodiment of the presentinvention, illustrating a method of changing a reflection spectrum byproviding a print layer (multi-level configuration).

FIG. 22 is a diagram illustrating an example of condition data inputtedto a computer to produce a two-dimensional barcode by demetallization.

FIG. 23 is a table showing a relationship among a demetallization amountin a metallic reflective layer, a recognition rate of a machine-readablecode, and visibility of a reconstructed image.

FIG. 24 is a cross-sectional view of an example in which a void having avoid size according to a phase angle is embedded in a pixel.

DETAILED DESCRIPTION

Embodiments of the present invention of will be described below withreference to the drawings. In the following description of the drawingsto be referred, components or functions identical with or similar toeach other are given the same or similar reference signs, unless thereis a reason not to. It should be noted that the drawings are onlyschematically illustrated, and thus the relationship between thicknessand two-dimensional size of the components, and the thickness ratiobetween the layers, are not to scale. Therefore, specific thicknessesand dimensions should be understood in view of the followingdescription. As a matter of course, dimensional relationships or ratiosmay be different between the drawings.

Further, the embodiments described below are merely examples ofconfigurations for embodying the technical idea of the presentinvention. The technical idea of the present invention does not limitthe materials, shapes, structures, arrangements, and the like of thecomponents to those described below. The technical idea of the presentinvention can be modified variously within the technical scope definedby the claims. The present invention is not limited to the followingembodiments within the scope not departing from the spirit of thepresent invention.

In any group of successive numerical value ranges described in thepresent specification, the upper limit value or lower limit value of onenumerical value range may be replaced with the upper limit value orlower limit value of another numerical value range. In the numericalvalue ranges described in the present specification, the upper limitvalues or lower limit values of the numerical value ranges may bereplaced with values shown in examples. The configuration according to acertain embodiment may be applied to other embodiments.

With reference to the accompanying drawings, some embodiments of thepresent invention will be described.

FIG. 1 is a conceptual diagram illustrating an integratedthree-dimensional display to which a method of recording identificationinformation according to an embodiment of the present invention isapplied

An integrated three-dimensional display 10 to which a method ofrecording identification information according to an embodiment of thepresent invention is applied includes a substrate 12 parallel to an xyplane shown in FIG. 1, and a recording surface 14 provided on thesubstrate 12. A multiple pixels g are arrayed in a matrix on therecording surface 14. Each pixel g can have a square shape with a sidelength p of a minimum resolution of an electron beam lithographyapparatus (possible range is 100 to 500 (nm)). Further, each pixel g mayhave a rectangular shape, and the corners thereof may be rounded.

The recording surface 14 includes a calculated element region 16, aphase angle recorded area 18, and a phase angle non-recorded area 20.The recording surface 14 can be covered with a metallic reflectivelayer.

The calculated element region 16 is a region defined by one-to-onecorrespondence to light converging points Sn (n is a positive integer)of a holographic reconstructed image 40, in which phase components oflight from the respective light converging points Sn are calculated. Theholographic reconstructed image 40 can be visible. The wavelength oflight reconstructing the hologram can be in a range of 470 (nm) or moreand 750 (nm) or less. The integrated three-dimensional display 10enables reading of three-dimensional information in the visible range. Asolid-state imaging camera can be used to read three-dimensionalinformation. The solid-state imaging camera may be a CCD camera or aCMOS camera. Further, the integrated three-dimensional display 10enables reading of three-dimensional information in the infrared rangeor ultraviolet range. An infrared camera can be used to readthree-dimensional information. The infrared camera may be a solid-stateimaging camera. When an ultraviolet lamp such as a black light is usedfor illumination so that ultraviolet light is converted into visiblelight or infrared light by fluorescent materials, the three-dimensionalinformation can be read in the ultraviolet range by using a solid-stateimaging camera.

The phase angle recorded area 18 is a region for recording a phase anglecalculated based on the phase components of light from each lightconverging point Sn and a pixel depth according to the phase angle. Theabove information is recorded in an overlap area in which the phaseangle recorded area 18 overlaps the calculated element region 16.

On the other hand, the phase angle non-recorded area 20 is a region inwhich information recorded in the phase angle recorded area 18 is notrecorded. That is, a phase angle calculated based on phase components oflight from each light converging point Sn and a pixel depth according tothe phase angle are not recorded in the phase angle non-recorded area20. However, other information such as scattering, reflection,diffraction and other properties of light can be recorded in the phaseangle non-recorded area 20. The phase angle non-recorded area 20 canhave a mirror surface.

A phase angle φ can be calculated according to the following formula.

$\begin{matrix}{{{W( {{kx},{ky}} )} = {\sum\limits_{n = 0}^{N\;\max}{\sum\limits_{{ky} = {Y\;\min}}^{Y\;\max}{\sum\limits_{{kx} = {X\;\min}}^{X\;\max}{{amp} \cdot {\exp( {i\;\phi} )}}}}}}{\phi = {\frac{\pi}{\lambda \cdot {O_{n}(z)}}\{ {( {{O_{n}(x)} - {kx}} )^{2} + ( {{O_{n}(y)} - {ky}} )^{2}} \}}}} & \lbrack {{Math}.\mspace{11mu} 3} \rbrack\end{matrix}$

In the above formula, (kx, ky) are coordinates of the pixel g, W (kx,ky) represents phase components of the coordinates (kx, ky), n is anindex of light converging points Sn (n=0 to Nmax), amp is the amplitudeof light at the light converging points Sn, i is the imaginary number, λis a wavelength of light in reconstruction of the reconstructed image40, On (x, y, z) represents coordinates of the light converging pointsSn, and Xmin, Xmax, Ymin, and Ymax are coordinates indicating the rangeof the calculated element region 16 defined for the respective lightconverging points Sn.

The phase angle φ obtained according to the above formula is recorded inthe corresponding pixel g in the overlap area of the phase anglerecorded area 18 which overlaps the calculated element region 16.

Further, the phase angle φ can be recorded in the corresponding pixel gin the overlap area as the depth of the pixel g according to the phaseangle φ. In this case, the phase angle φ is converted into a depth ofthe pixel g. This is performed by a computer calculating the phase angleφ in the range of 0π to 2π, and converting the resultant value into an8-bit grayscale value in order to output the calculation results. Inthis case, 2π corresponds to the level 255 of 8-bit grayscale values.Then, based on the results of the calculation, an image is drawn on aresist substrate with an electron beam lithography apparatus.

If the electron beam lithography apparatus is not compatible withmulti-level drawing, drawing similar to multi-level drawing is performedby drawing an image multiple times at the same position with differentpower outputs. Drawing three times can achieve an appearancecorresponding to multi-level drawing having eight levels. Then, theresist is developed to obtain a substrate having a uneven structure. Thesubstrate having a uneven structure is subjected to electrocasting toobtain a stamper. In drawing on the resist substrate, the phase anglecan be recorded by four or eight-level drawing. Specifically, the unevenstructure of the monochromatic region 22 can have two levels.

In order to change the color by the depth of the pixel g, drawing twolevels at the same time is necessary. In this case, drawing can beperformed by binarizing the gray scale which is a design value. That is,the concave portions of the uneven structure of the monochromatic region22 have a constant depth. Further, the protrusion portions of the unevenstructure of the monochromatic region 22 have a constant height.

The depth of the pixel g which forms a recess can be controlled bymodulating the dose of the electron beam. The depth of drawing on theresist substrate changes with the dose. Thus, the recess of the depth ofthe pixel g on the recording surface 14 can be recorded.

The above stamper is used to form a uneven structure on a thermoplasticresin, heat-curable resin, UV resin, or the like in the pixels g in theoverlap area, which is provided facing the resist substrate. Thus, theuneven structure of an embossed layer can be formed by embossing withthe stamper. The embossing can be hot embossing. Ultraviolet radiationcan be applied either during or after embossing, or both during andafter embossing. The stamper may be heated or cooled during embossing.Thus, the depth of the pixels g according to the phase angle φ can berecorded in the pixels g in the overlap area.

FIG. 2 is a cross-sectional view illustrating a portion of the overlaparea in which a depth of a pixel according to a phase angle is recorded.

FIG. 2 illustrates an example cross-sectional configuration of theoverlap area 19, in which a release layer 27, an embossed layer 23, areflective layer 24, and an adhesive layer 25 are laminated in thisorder from the upper side in the drawing. Among these layers, theembossed layer 23 and the reflective layer 24 correspond to therecording surface 14. The substrate 12 is not shown in the figure. Thedepth of the pixel g in the embossed layer 23 corresponds to the phaseangle cp. The adhesive layer 25 can fix the integrated three-dimensionaldisplay 10 to an object 26, and the release layer 27 can protect asurface of the embossed layer 23. In this configuration, an interfacebetween the embossed layer 23 and the reflective layer 24 corresponds tothe recording surface 14.

The overlap area 19 includes one or more monochromatic regions 22, eachcomposed of a group of pixels g, extending parallel to the xy plane.Further, the embossed layer 23 in the same monochromatic region 22 has aconstant depth T. That is, in FIG. 2, which illustrates twomonochromatic regions 22 (#1) and (#2), the pixels g of the embossedlayer 23 in the monochromatic region 22(#1) have a depth T1, whereas thepixels g in the embossed layer 23 of the monochromatic region 22 (#2)have a depth T2 larger than the depth T1 (T2>T1). The pixels g of theembossed layer 23 are arrayed in the x and y directions such that theconcave portions and protrusion portions are alternately arranged at apitch that is an integral multiple of a side length p of the pixel g (p,2p, 3p, . . . ).

The reflective layer 24 made of a metal or a metal compound is disposedbetween the embossed layer 23 and the adhesive layer 25, and a surfaceof the embossed layer 23 opposite to that facing the adhesive layer 25is covered with the release layer 27. The metal of the reflective layer24 can be aluminum, silver, gold or the like. The metal of thereflective layer 24 can be a metal sulfide, a metal oxide, a metalnitride, or the like. The metal sulfide can be zinc sulfide or the like.The metal oxide can be alumina, titanium oxide, or the like. The metalnitride can be calcium nitride, aluminum nitride, or the like. Since themetallic reflective layer easily absorbs laser light, it is suitable forlaser engraving.

The type of the monochromatic region 22 is determined depending on thedepth T of the pixels g of the embossed layer 23. Although the exampleshown in FIG. 2 includes only two types of monochromatic regions 22, orthe monochromatic region 22 (#1) in which the pixels g have the depth T1and the monochromatic region 22 (#2) in which the pixels g have thedepth T2, the number of types of the monochromatic regions 22 in theintegrated three-dimensional display 10 is equal to the number of colorsrequired to reconstruct the reconstructed image 40. When the threecolors of RGB are applied to reconstruct the reconstructed image 40,three monochromatic regions 22 in which the respective embossed layers23 have different depths T can be provided as the monochromatic regions22 corresponding to the three colors of RGB. The depth of the pixels gcan be in the range of 78 (nm) or more and 250 (nm) or less. Thisapplies to the case where the visible light from blue to red ranges from470 (nm) to 750 (nm), the embossed layer 23 has a refractive index of1.5, and the required depth of the structure is from ¼λ to ½λ.

In the example shown in FIG. 2, the pixel g of the embossed layer 23 inthe monochromatic region 22 (#1) has a depth T1 that reflects light of acenter wavelength and the pixel g of the embossed layer 23 in themonochromatic region 22 (#2) has a depth T2 that reflects light of acenter wavelength λ2.

Further, although the example shown in FIG. 2 includes only two adjacentmonochromatic regions 22 (#1) and (#2), a plurality of the same type ofmonochromatic regions 22 can be provided parallel to the xy plane in theoverlap area 19. The monochromatic regions 22 can be arranged adjacentto each other. Further, the adjacent monochromatic regions 22 can beformed on the recording surface 14 as an integrated unit.

Thus, the depth T according to the phase angle φ calculated at thecoordinates of each pixel g can be recorded in the pixel g constitutingthe monochromatic region 22.

Further, the pixels g are disposed to form a zone plate around a pointC1 in monochromatic region 22 (#1), and the pixels g are disposed toform a zone plate around a point C2 in the monochromatic region 22 (#2).

The point C1 is an intersection between a line from the light convergingpoint S1 perpendicular to the recording surface 14 and a surface of therecording surface 14. Similarly, the point C2 is an intersection betweena line from the light converging point S2 perpendicular to the recordingsurface 14 and a surface of the recording surface 14. The line from thelight converging point S1 perpendicular to a surface of the recordingsurface 14 has a length Z1, and the line from the light converging pointS2 perpendicular to a surface of the recording surface 14 has a lengthZ2.

In addition, the pixels g are disposed to form a zone plate around apoint C2 in monochromatic region 22 (#1), and the pixels g are disposedto form a zone plate around a point C1 in the monochromatic region 22(#2). In other words, the monochromatic region 22 (#1) and themonochromatic region 22 (#2) are arrayed in a phase-continuous manner.The spatial frequencies of the zone plate increase from the centertoward the periphery. The spatial frequencies affect the wavelength ofreflected light converging on the light converging point S of themonochromatic region 22. Particularly, in a region of the zone platehaving too high spatial frequencies, diffraction causes significantinfluence. Accordingly, in view of reducing this influence, the spatialfrequencies of the zone plate can be 500 (lp/mm) or less.

With this configuration, even when light reflected from differentmonochromatic regions 22 converges on the respective light convergingpoints at specific distances Zn from the recording surface 14, which aredetermined for each of the light converging points. All the distances Zn(n is a natural number) can be in the range of 0.5 (mm) or more and 50(mm) or less. The reason for this is that, when white light is used forreconstruction, the reconstruction distance is not too great, so thecolors of image are not separated into RGB, preventing deterioration inimage quality due to color separation. Further, since athree-dimensional image can be distinguished from a planar image, theimage can be recognized as a three-dimensional image.

Moreover, the reflective layer 24 can be partially removed to record amark, a shape, a code, or the like. A laser used for the above recordingmay be an infrared laser. The beam emitted from the infrared laser ontothe reflective layer 24 can apply heat energy required to remove thereflective layer 24. The infrared laser can be a solid-state laser. Asthe solid-state laser, a general YAG laser can be used. A YAG laser hasa fundamental wavelength of 1064 (nm). Further, when the embossed layer23 is a polymer, it typically has a refractive index of approximately1.5. Therefore, assuming that the refractive index of the embossed layer23 is 1.5, the wavelength in the embossed layer 23 is 709 (nm). Whenlight is perpendicularly incident on the embossed layer 23, thereflection of light is maximized under the condition that the pixel hasa depth of 354 (nm), which is half the wavelength of the laser in theembossed layer 23. On the other hand, when the structure has a depth of177 (nm), reflection of light is minimized.

Therefore, when the structure has a depth of 89 (nm) or more and 266(nm) or less, laser light is easily absorbed. Within this range, thereflective layer 24 can be partially removed under the same engravingcondition even if the structure is different. Further, the pixel depthin view of the requirement for reconstruction of a visible hologram is78 (nm) or more and 250 (nm) or less, and the pixel depth in view of therequirement for engraving is 89 (nm) or more and 266 (nm) or less.Accordingly, both requirements can be satisfied when the depth is 89(nm) or more and 250 (nm) or less.

As described above, the integrated three-dimensional display 10 enablesreconstruction of a visible hologram, and recording of two-dimensionalinformation on the reflective layer 24 by a laser. Further, when thestructure has a depth or height of 350 (nm) or more, embossing becomesdifficult.

As described above, light reflected on the plurality of monochromaticregions 22 converges on the respective specific light converging pointsS1, S2, . . . Sn. FIG. 2 illustrates that propagation light which islight reflected from the monochromatic region 22 (#1) and propagationlight which is light reflected from the monochromatic region 22 (#2)both converge on the light converging points S1 and S2. That is, in theexample of FIG. 2, the propagation light from the plurality ofmonochromatic regions 22 (#1 and #2) converges on the light convergingpoint S1 common to the plurality of monochromatic regions 22 (#1 and#2). Similarly, the propagation light from the plurality ofmonochromatic regions 22 (#1 and #2) converges on the light convergingpoint S2 common to the plurality of monochromatic regions 22 (#1 and#2). That is, the propagation light is directed from the reflectivelayer 24 and converges on the light converging points S, which areseparated from each other.

FIG. 3 is a front view of a reconstructed image produced by anintegrated three-dimensional display which includes an overlap areahaving an example configuration shown in FIG. 2 viewed from above (inthe Z direction).

The figure shows that light reflected from the monochromatic regions 22(#1) and (#2) respectively converges on the light converging points S1and S2.

Next, a principle of full-color display achieved by an integratedthree-dimensional display according to an embodiment of the presentinvention will be described.

FIG. 4 is a conceptual diagram illustrating a principle of full-colordisplay achieved by an integrated three-dimensional display according toan embodiment of the present invention.

As described above, the number of types of the monochromatic regions 22in the integrated three-dimensional display 10 is equal to the number ofcolors required to reconstruct the reconstructed image 40. In addition,the number and arrangement of the monochromatic regions 22 in theintegrated three-dimensional display 10 can be changed according to themark or machine-readable code to be represented.

The colors required to reconstruct the reconstructed image 40 can be thethree RGB colors, and the monochromatic regions 22 can be of a size thatis not recognizable by human eyes. The size that is not recognizable byhuman eyes can be 100 (μm) or less. When the monochromatic regions 22having such a size are arranged in the xy plane, white is observed underdiffuse illumination, whereas the three-dimensional reconstructed image40 can be reconstructed in full color by the respective colors of lightconverging points Sn under a point light source. With reference to FIGS.5A, 5B, and 5C, example arrangements of the monochromatic regions 22 inthe overlap area 19 will be described.

FIG. 5A is a conceptual diagram illustrating an example arrangement of amonochromatic region that causes the light converging point S1 to emitred light.

FIG. 5B is a conceptual diagram illustrating an example arrangement of amonochromatic region that causes the light converging point S2 to emitblue light.

FIG. 5C is a conceptual diagram illustrating an example arrangement of amonochromatic region that causes the light converging point S3 to emitviolet light.

As shown in FIG. 5A, in order to cause the light converging point S1 toemit red light, only the monochromatic regions 22 (#1) that reflect redlight are disposed in an overlap area 19A in which the calculatedelement region 16 defined by the light converging points S1 overlaps thephase angle recorded area 18.

As shown in FIG. 5B, in order to cause the light converging point S2 toemit blue light, only the monochromatic regions 22 (#2) that reflectblue light are disposed in an overlap area 19B in which the calculatedelement region 16 defined by the light converging points S2 overlaps thephase angle recorded area 18.

On the other hand, violet is a color obtained by mixing red and blue.Accordingly, as shown in FIG. 5C, in order to cause the light convergingpoint S3 to emit violet light, the monochromatic regions 22 (#1) thatreflect red light and the monochromatic regions 22 (#2) that reflectblue light are disposed in an overlap area 19C in which the calculatedelement region 16 defined by the light converging points S3 overlaps thephase angle recorded area 18.

Further, as shown in FIG. 6, the phase angle recorded area 18 includesan RGB color conversion region 21 in which red regions R, green regionsG, and blue regions B are repeatedly arranged in the vertical directionin the figure. Kinoform lenses according to the intensity of each RGBcolor are provided to reconstruct the three-dimensional reconstructedimage 40 in full RGB colors. FIG. 7 differs from FIG. 6 in that the datarecorded in a color conversion region 21 (#1), which corresponds to thecolor conversion region 21 of FIG. 6, is copied to a horizontallyadjacent position to form a color conversion region 21 (#2) adjacent tothe color conversion region 21 (#1). Accordingly, the luminescence ofthe reconstruction positions can be made twice that of FIG. 6.

In FIG. 8, the regions which correspond to the RGB regions in the colorconversion region 21 of FIG. 6 are all replaced with the green regionsG, i. e., the data recorded in the green region G of FIG. 6 is copiedthe adjacent red and blue regions R and B. Accordingly, the luminescenceof green components can be made three times higher than in FIG. 6.

FIG. 6 illustrates the color conversion region 21, in which the redregions R, the green regions G, and the blue regions B are regularlyrepeated in the vertical direction. On the other hand, as shown in FIG.9, the red regions R, the green regions G, and the blue regions B can berandomly disposed in the color conversion region 21. With this randomarrangement, the RGB ratio can be freely changed without changing thearrangement of the color conversion regions 21.

FIG. 10(a) illustrates an example, which differs from FIG. 9 in that thered regions R, the green regions G, and the blue regions B are regularlyarranged in the color conversion region 21. However, instead of the samepattern of pixels g, a plurality of patterns of pixels g1 and g2 asshown in FIG. 10(b) are arranged in the color conversion region 21. Thepixels g1 and g2 both have an L-shape, but are different in the patternof RGB arrangement. The pixel g1 is an L-shaped pixel in which the greenregion G is located at the center, and the blue region B and the redpixel R are located adjacent to the green region G. On the other hand,the pixel g2 is an L-shaped pixel in which the blue region B is locatedat the center, and the green region G and the red pixel R are locatedadjacent to the blue region B. Although FIG. 10(b) shows only twopatterns of the pixels g1 and g2, the pattern of pixels and the numberof patterns are merely examples, and a plurality of patterns of pixels gcan be arranged in any way in the color conversion region 21.

Moreover, two or more regions having different arrangements may also beprovided. A mark can be formed by such different arrangements. The markthus formed can be characters, codes, landmarks, portraits, symbols, orthe like.

When RGB=(255, 255, 255) in the digital image, for example, recording ofRGB=(10, 20, 30) can be achieved by adjusting the recording area in themonochromatic region 22. For example, recording can be performed at thearea ratio of (10/255, 20/255, 30/255). Further, in addition to themethod of recording by adjusting the area, the above amp (amplitude oflight at the light converging point) can also be adjusted.

FIG. 11 is a conceptual diagram illustrating an integratedthree-dimensional display 10 having six types of monochromatic regions22 (#1), (#2), (#3), (#4), (#5), and (#6) for reflected light of sixwavelengths.

FIG. 11 illustrates an example in which six monochromatic regions 22(#1), (#2), (#3), (#4), (#5), and (#6) having a rectangular shapeelongated in the X axis direction are stacked in the Y axis direction.However, these are merely examples, and other arrangements are alsopossible.

FIG. 12 is a conceptual diagram illustrating that different colors aredisplayed depending on the viewing position.

According to the configuration of FIG. 11, one light converging point S1is reconstructed in six different colors depending on the viewingdirection as shown in FIG. 12.

FIG. 13 is a conceptual diagram illustrating that two-dimensionalinformation having a shape representing a mark is applied to anintegrated three-dimensional display.

Two-dimensional information 50 can be imparted to the integratedthree-dimensional display 10 by being printed on a print layer (notshown) on a side of the recording surface 14 facing the observer, i. e.,the light converging point Sn. Alternatively, the two-dimensionalinformation 50 can be imparted to the integrated three-dimensionaldisplay 10 by demetallizing the metallic reflective layer 24 using alaser to remove metal from the reflective layer 24 to thereby controlreflection of light.

The two-dimensional information 50 is not limited to a shaperepresenting a mark, and can be a shape representing a character or ashape representing a machine-readable code. These marks, characters, andpatterns can be applied as personal identification information.

According to the configuration shown in FIG. 13, in which thetwo-dimensional information 50 and the information for convergingreflected light to the light converging point Sn are located in the sameregion, high anti-counterfeiting properties can be achieved. Sinceconverging light to the light converging point Sn acts to reconstructthe three-dimensional reconstructed image 40, the information forconverging reflected light to the light converging point Sn correspondsto three-dimensional information. That is, FIG. 13 illustrates aconfiguration in which the two-dimensional information 50 and thethree-dimensional information are located in the same region in order toachieve high anti-counterfeiting properties.

FIGS. 14A(a) and (b) are a cross-sectional view and a plan viewillustrating an example positional relationship between thetwo-dimensional information 50 and the three-dimensionally distributedlight converging points S (S1 to Sn), which do not overlap each other inthe xy plane.

FIGS. 14B(a) and (b) are a conceptual diagram illustrating an examplepositional relationship between the two-dimensional information 50 andthe three-dimensionally distributed light converging points S (S1 toSn), which overlap each other in the xy plane.

The cross-sectional views shown in FIG. 14A(a) and FIG. 14B(a) are takenalong the line W1-W1 and the line W2-W2 in FIG. 14A(b) and FIG. 14B(b),respectively, and illustrate the positional relationship between therecording surface 14 and the light converging point S in the zdirection, i. e., the depth direction of the recording surface 14. Theplan views shown in FIG. 14A(b) and FIG. 14B(b) illustrate thepositional relationship between the overlap area 19 and thetwo-dimensional information 50 in the xy plane.

According to the configuration shown in FIGS. 14A (a) and (b), in whichthe two-dimensional information 50 and the three-dimensional informationare separated in the xy plane, only the two-dimensional information 50can be counterfeited, while the genuine three-dimensional informationmay remain unchanged. Therefore, anti-counterfeiting properties arepoor.

On the other hand, according to the configuration shown in FIGS. 14B (a)and (b), the two-dimensional information 50 and three-dimensionalinformation are arranged at least partially overlapping each other inthe depth direction of the recording surface 14. Therefore, since it isdifficult to counterfeit both the two-dimensional information 50 andthree-dimensional information, anti-counterfeiting properties can beimproved.

FIGS. 15A and 15B are conceptual diagrams illustrating a positionalrelationship between the overlap area 19 and the two-dimensionalinformation 50 on the recording surface 14.

FIG. 15A illustrates a state in which only part of the overlap area 19overlaps the two-dimensional information 50, i. e., the two-dimensionalinformation 50 does not overlap the entire surface of the overlap area19. FIG. 15B illustrates a state in which the entire surface of theoverlap area 19 is covered with the two-dimensional information 50.

As shown in FIG. 15B, when the entire surface of the overlap area 19 iscovered with the two-dimensional information 50, the light convergingpoint Sn cannot be reconstructed since the overlap area 19 cannot beused. On the other hand, in the positional relationship shown in FIG.15A, even when part of the overlap area 19 is covered with thetwo-dimensional information 50, the light converging point Sn can bereconstructed by using a portion of the overlap area 19 which is notcovered with the two-dimensional information 50. Therefore, forrecording of the two-dimensional information 50 in the recording surface14, the two-dimensional information 50 is positioned without coveringthe entire surface of the overlap area 19 as shown in FIG. 15A.

FIGS. 16A (a) and (b) and 16B (a) and (b) are cross-sectional views andplan views illustrating an embodiment of an authentication medium inwhich the two-dimensional information 50 and the three-dimensionallydistributed points S (S1 to Sn) are located overlapping each other inthe xy plane.

The cross-sectional views shown in FIG. 16A(a) and FIG. 16B(a) are takenalong the line W3-W3 and the line W4-W4 of FIG. 16A(b) and FIG. 16B(b),respectively, and an authentication medium 60 shown in the figuresincludes the integrated three-dimensional display 10 attached to theobject 26. In particular, as clearly shown in FIG. 16A(b) and FIG.16B(b), the overlap area 19 includes three types of monochromaticregions 22 (#1), (#2), and (#3) having a vertically long rectangularshape of the same size, which are arranged in this order from the leftto the right in the figure without overlapping each other. These threetypes of monochromatic regions 22 (#1), (#2), and (#3) can be colored indifferent colors.

The two-dimensional information 50 can be imparted to the authenticationmedium 60 by providing a print layer (not shown) on the upper surface ofthe overlap area 19, and printing the two-dimensional information 50 onthe print layer. Alternatively, the two-dimensional information 50 canalso be imparted to the authentication medium 60 by demetallizing themetallic reflective layer 24 instead of providing a print layer.

These two-dimensional information 50 can display a mark or atwo-dimensional barcode. FIG. 16A(b) illustrates a case where thetwo-dimensional information 50 is a mark, and FIG. 16B(b) illustrates acase where the two-dimensional information 50 is a barcode.

The two-dimensional information 50 is positioned in a configurationshown in FIG. 15A, in which at least part of the overlap area 19 is notcovered with the two-dimensional information 50, rather than aconfiguration shown in FIG. 15B, in which the entire surface of theoverlap area 19 is covered with the two-dimensional information 50. Withthis configuration, the two-dimensional information 50 can be impartedto the integrated three-dimensional display 10 without causing the lightconverging point Sn to disappear.

FIGS. 17A(a) and (b) are a cross-sectional view and a plan viewillustrating an embodiment of an authentication medium having a markrepresented by a planar shape of a monochromatic region.

FIG. 17A(a) shows a cross-sectional view taken along the line W5-W5 inFIG. 17A(b).

According to an authentication medium illustrated in FIGS. 17A(a) and(b), particularly as shown in FIG. 17A(b), a mark is represented byplanar shapes of the monochromatic regions 22 (#1), (#2), and (#3)disposed in the overlap area 19. Similarly, not only marks, but alsocharacters or machine-readable codes can be represented by the planarshapes or configurations of a plurality of types of monochromaticregions 22. Such marks, characters, or codes can be provided withpersonal identification information to thereby provide theauthentication medium 60 with personal identification information.

FIGS. 17B (a) and (b) are a cross-sectional view and a plan viewillustrating an embodiment of an authentication medium having a mark anda barcode pattern represented by a planar shape of a monochromaticregion.

FIG. 17B(a) shows a cross-sectional view taken along the line W6-W6 inFIG. 17B(b).

In the authentication medium 60 shown in FIGS. 17B (a) and (b), a printlayer (not shown) is provided on the upper surface of the overlap area19 on the authentication medium 60 shown in FIGS. 17A (a) and (b), as inFIGS. 16B (a) and (b), and the two-dimensional information (barcodeinformation) 50 is printed on the print layer.

FIGS. 18A, 18B, and 18C are conceptual diagrams illustrating that thethree-dimensional image 40 is reconstructed across a plurality ofmonochromatic regions 22 (#1) and (#2) having different reconstructedcolors.

As shown in front views in FIGS. 18A, 18B, and 18C, the monochromaticregion 22 (#1) is positioned on the left half of the integratedthree-dimensional display 10 (overlap area 19), and the monochromaticregion 22 (#2) is positioned on the right half. The reflected light fromthe monochromatic region 22 (#1) converges on the light converging pointSn as a first reconstruction color (for example, red), and the reflectedlight from the monochromatic region 22 (#2) converges on the lightconverging point Sn as a second reconstruction color (for example, blue)to thereby reconstruct the reconstructed image 40.

FIG. 18B shows a side view illustrating the integrated three-dimensionaldisplay 10 observed by an observer 90 with a viewing directionperpendicular to the center of the front surface of the integratedthree-dimensional display 10. In this case, as shown in the front viewof FIG. 18B, the reconstructed image 40 observed is located at thecenter of the integrated three-dimensional display 10 with the left halfbeing displayed in a first color and the right half being displayed in asecond color.

FIG. 18A shows a side view illustrating the integrated three-dimensionaldisplay 10 observed by the observer 90 with a viewing direction which isobliquely directed from an upper right position relative to the centerof the integrated three-dimensional display 10 in the figure in anangular range of 0(°) or more and 70(°) or less relative to a surface ofthe integrated three-dimensional display 10. In this case, as shown inthe front view of FIG. 18A, the reconstructed image 40 observed islocated shifted to the left from the center of the integratedthree-dimensional display 10, and accordingly, the area displayed in afirst color increases and the area displayed in a second color decreasescompared to those shown in FIG. 18B.

On the other hand, FIG. 18C shows a side view illustrating theintegrated three-dimensional display 10 observed by the observer 90 witha viewing direction which is obliquely directed from an upper leftposition relative to the center of the integrated three-dimensionaldisplay 10 in the figure in an angular range of 0(°) or more and 70(°)or less relative to a surface of the integrated three-dimensionaldisplay 10. In this case, as shown in the front view of FIG. 18C, thereconstructed image 40 observed is located shifted to the right from thecenter of the integrated three-dimensional display 10, and accordingly,the area displayed in a second color increases and the area displayed ina first color decreases compared to those shown in FIG. 18B.

The three-dimensional information represented by the reconstructed image40 is not limited to characters and marks, and can also be used aspatterns representing machine-verifiable information such as QR codes,barcodes, data matrices or the like. Further, by verifying theintegrated three-dimensional display 10 using the three-dimensionalposition coordinates of the light converging point Sn to determinewhether it is genuine or counterfeit, high security can be achieved.

As described above, the three-dimensional information of thereconstructed image 40 can be authentication information. Further, whentwo-dimensional information representing identification information isrecorded in the monochromatic region 22 that displays the reconstructedimage 40 of three-dimensional information, the authenticationinformation and the identification information can be inseparablyintegrated. Since a barcode includes bars arranged at predeterminedintervals, the phase angle recorded area 18 is distributed when recordedon the reflective layer 24 of the recording surface 14. Accordingly, itis possible to prevent the entire reflective layer 24 from being removedin the region in which a zone plate is provided that reflects light fromthe recording surface 14 onto a single light converging point S.

The barcode can be JAN/EAN/UPC applied to a distribution code, ITFapplied as a logistics product code, CODE39 applied as an industrialbarcode, NW-7 applied to a delivery slip, or the like. Further, thebarcode can include an error detection code or an error correction code.That is, it can include redundancy. In addition, although a barcode canbinarize the reflectance so that data can be read as ON and OFF levels,it can also read multivalued reflectance. In addition, thetwo-dimensional information can be recorded across a plurality ofmonochromatic regions 22. Since forming a plurality of monochromaticregions 22 requires advanced processing technology, it can preventcounterfeiting of the two-dimensional information by recording thetwo-dimensional information across a plurality of monochromatic regions22. Further, when the two-dimensional information is identificationinformation, imposter scams using counterfeit identification informationcan be prevented.

Examples of the method of obtaining three-dimensional positioncoordinates include a method using a stereo camera, a method using aKinect sensor which is commercially available, and a method by a scan inthe depth direction using a transmissive pixel scanner.

Then, the three-dimensional position coordinates thus obtained can besubjected to arithmetic processing by using a point cloud library or thelike to estimate three-dimensional features such as SHOT (signature ofhistograms of orientations) features, PFH (point feature histograms)features, and PPF (point pair feature) features, and compare thefeatures with the correct three-dimensional position coordinates storedin the database to thereby determine whether the authentication medium60 is genuine or counterfeit.

Next, a method of changing the properties of reflected light, i.e., areflection spectrum without changing the depth T of the embossed layer23 will be described.

In the above description in connection with FIG. 2 and the like, themethod of changing the properties of reflected light, i.e., a reflectionspectrum by changing the depth T of the embossed layer 23, has beendescribed. However, the reflection spectrum can also be changed bydemetallizing the metallic reflective layer 24 or by providing a printlayer 28 without changing the depth T of the embossed layer 23.

With reference to FIGS. 19A and 19B, the method of changing thereflection spectrum by demetallizing the metallic reflective layer 24will be described.

FIG. 19A is a cross-sectional view of an example of an integratedthree-dimensional display according to an embodiment of the presentinvention, illustrating an example method of changing a reflectionspectrum by demetallization.

FIG. 19A illustrates a cross-sectional configuration of an integratedthree-dimensional display, in which the release layer 27 and theembossed layer 23 are laminated in this order on the substrate 12.Further, the embossed layer 23 is covered with the reflective layer 24.The reflective layer 24 is further covered with an adhesive layer.

Further, three monochromatic regions 22 (#1), (#2), and (#3) arearranged in this order in the x direction in the figure, each havingtheir own value as a depth T of the embossed layer 23 in the samemonochromatic region 22. In FIG. 19A, the embossed layer 23 in themonochromatic region 22 (#1) has a depth T1, the embossed layer 23 inthe monochromatic region 22 (#2) has a depth T2, and the embossed layer23 in the monochromatic region 22 (#3) has a depth T3, having therelationship of T2>T1>T3.

On the other hand, FIG. 19B is a cross-sectional view illustrating anembodiment in which part of the metal is removed by demetallizing partof the metallic reflective layer 24 shown in FIG. 19A. In this case, anadhesive layer is positioned on the reflective layer 24 or the embossedlayer 23. The demetallization can be performed by laser engraving.

As the metallic reflective layer 24 is demetallized as shown in FIG. 19Bfrom the configuration shown in FIG. 19A, the reflection spectrum of theembossed layer can be changed.

Such a mechanism by which the reflection spectrum changes due todemetallization will be described below with reference to FIGS. 20A and20B.

FIG. 20A is a conceptual diagram illustrating inspection light α emittedfrom an authentication device 70 being reflected by the reflective layer24.

FIG. 20B is a conceptual diagram illustrating inspection light a emittedfrom the authentication device 70 being transmitted through ademetallized section 30.

FIG. 20A and FIG. 20B illustrate cross-sectional configurations of anintegrated three-dimensional display 11, in which the substrate 12 isremoved from the cross-sectional configuration shown in FIG. 19B, andthe object 26 is adhered to the adhesive layer 25. In FIG. 20A, ademetallized portion of the metallic reflective layer 24 is indicated asthe demetallized section 30.

The integrated three-dimensional display 11 is used to record amachine-readable code 80 shown in FIG. 20A and FIG. 20B by using thechange in reflection spectrum due to demetallization.

The authentication device 70 is an apparatus configured to emitinspection light α toward the integrated three-dimensional display 11and detect reflected light β from the integrated three-dimensionaldisplay 11 to thereby read a pattern of the machine-readable code, andmay be, but is not limited to, a smartphone, a cash register reader, anoptical spectrum device, or the like.

In this case, the authentication device 70 reads the pattern of themachine-readable code preferably in an angular range of 0(°) or more and70(°) or less relative to the recording surface 14.

Since the inspection light α emitted from the authentication device 70is reflected by the reflective layer 24 as shown in FIG. 20A, reflectedlight β does not return to the authentication device 70. Accordingly, asillustrated in FIG. 20B, the reflective layer 24 is recognized by theauthentication device 70 as a portion corresponding to black in themachine-readable code.

On the other hand, the inspection light α emitted from theauthentication device 70 is transmitted in the demetallized section 30as illustrated in FIG. 20B, and reflected by the underlying object 26.In particular, when the object 26 is white, the inspection light α isscattered on a surface of the object 26 to generate scattered light γ.The scattered light γ returns to the authentication device 70, and isrecognized as white by the authentication device 70. Accordingly, asillustrated in FIG. 20B, the demetallized section 30 is recognized bythe authentication device 70 as a portion corresponding to white in themachine-readable code.

Next, with reference to FIGS. 21A and 21B, a method of changing thereflection spectrum by providing a print layer will be described.

FIGS. 21A and 21B are cross-sectional views of one embodiment of anintegrated three-dimensional display according to an embodiment of thepresent invention, illustrating a method of changing a reflectionspectrum by providing a print layer.

FIG. 21A shows a cross-sectional configuration, in which the print layer28 is added between the release layer 27 and the embossed layer 23 inthe configuration having the monochromatic region 22 shown in FIG. 19A.In this configuration, the reflection spectrum can be changed byproviding the print layer 28 without changing the depth T of theembossed layer 23, and can also be changed by combination of the colorof reflected light determined by the depth T of the embossed layer 23with the print color. In addition, when the print layer 28 is added, themonochromatic region 22 may not be necessarily provided, and amulti-level configuration, in which the embossed layer 23 has aplurality of different depths T randomly distributed over the entiresurface, as shown in FIG. 21B, is also possible.

Next, demetallization performed by a computer will be described below.

FIG. 22 is a diagram illustrating an example condition data inputted toa computer to produce a two-dimensional barcode by demetallization. InFIG. 22, a white portion corresponds to a portion that is instructed tokeep a metal in the metallic reflective layer 24, and a black portioncorresponds to a portion that is instructed to demetallize a metal inthe metallic reflective layer 24.

According to this condition data, a computer does not demetallize ametal of the reflective layer 24 corresponding to a white portion shownin FIG. 22, and demetallizes only a metal of the reflective layer 24corresponding to a black portion shown in FIG. 22.

The portion which is not demetallized is recognized as a black portionas described above using FIG. 20A, while the portion which isdemetallized is recognized as a white portion as described above usingFIG. 20B.

Thus, the machine-readable code can be recorded by demetallizing ametal.

The recognition rate of the machine-readable code by the authenticationdevice 70, and visibility of the reconstructed image 40 depend on thedemetallization amount. When a metal section area before demetallizationis S1 and a metal section area after demetallization is S2, thedemetallization amount is defined by the following formula:demetallization amount (%)=(S1−S2)/S1. Further, the recognition rate isa ratio of recognized codes among the read codes.

FIG. 23 is a table showing a relationship among the demetallizationamount in the portion of the metallic reflective layer 24 that isdesired to be non-reflective, the recognition rate of themachine-readable code, and visibility of the reconstructed image 40.

As the demetallization amount of the metallic reflective layer 24increases, the contrast of the machine-readable code increases. Thisfacilitates authentication of the machine-readable code and increasesthe recognition rate per unit time, but decreases the brightness of thereconstructed image 40 and thus visibility of the reconstructed image40.

In contrast, as the demetallization amount decreases, the brightness ofthe reconstructed image 40 increases, which increases visibility of thereconstructed image 40, whereas the contrast of the machine-readablecode decreases and thus the recognition rate decreases.

FIG. 23 shows that both of good recognition rate and visibility of thereconstructed image 40 can be achieved when the demetallization amountin the portion of the metallic reflective layer 24 that is desired to benon-reflective is in the range of 30(%) or more and 70(%) or less.

Therefore, according to the integrated three-dimensional display of anembodiment of the present invention, demetallization is performed to30(%) or more and 70(%) or less of a metal of the metallic reflectivelayer 24 that is desired to be non-reflective (for example, a portion ofthe machine-readable code to be displayed in white).

Next, materials of components of the integrated three-dimensionaldisplay according to an embodiment of the present invention will bedescribed.

A material used for the substrate 12 can be a rigid material such as aglass substrate, or a film substrate. The substrate 12 may be a plasticfilm such as of PET (polyethylene terephthalate), PEN (polyethylenenaphthalate), or PP (polypropylene). Preferably, the material of thesubstrate 12 may be one that is less likely to deform or alter due toheat, pressure, or the like applied at the time of providing therecording surface 14. Depending on the usage or purpose, paper,synthetic paper, plastic multilayer paper, resin-impregnated paper, orthe like may be used as the substrate 12.

The release layer 27 can be formed of a resin and a lubricant. The resinmay preferably be a thermoplastic resin, a thermosetting resin, anultraviolet curable resin, or an electron beam curable resin. The resincan be an acrylic resin, a polyester resin, or a polyamide resin. Thelubricant may preferably be a wax of polyethylene powder, a paraffinwax, silicone, carnauba wax, or the like. These materials may be appliedto the substrate 12 by a known coating method such as gravure printingor micro gravure printing to form the release layer 27. The releaselayer 27 can have a thickness in the range of 0.1 (μm) or more and 2(μm) or less. The release layer 27 can be provided with hard coatingproperties to protect the recording surface 14 and the two-dimensionalinformation. The hard coating properties may refer to the hardness inthe range of H or more and 5H or less in the pencil hardness test (JISK5600-5-4).

The embossed layer 23 may have a resin matrix. The resin may preferablybe a thermoplastic resin, a thermosetting resin, an ultraviolet curableresin, a thermoformable material having a radically polymerizableunsaturated group, an electron beam curable resin, or the like. Resinsthat can be used may be urethane resins, polycarbonate resins,polystyrene resins, thermoplastic resins of polyvinyl chloride resins,unsaturated polyester resins, melamine resins, epoxy resins, urethane(meth)acrylate, polyester (meth)acrylate, epoxy (meth)acrylate, polyol(meth)acrylate, melamine (meth)acrylate, or triazine (meth)acrylate. Theembossed layer 23 can have a thickness in the range of 0.5 (μm) or moreand 5 (μm) or less.

The reflective layer 24 can be made of a metal. The metallic reflectivelayer 24 easily absorbs laser light, and is suitable for laserengraving. Examples of the metallic reflective layer 24 includealuminum, silver, tin, chromium, nickel, copper, and gold. Further, thematerial of the reflective layer 24 can be a metal compound. Examples ofthe metal compound reflective layer 24 include zinc sulfide, titaniumoxide, silicon oxide, and iron oxide. Further, the silicon oxide can beS1 ₂O₃, SiO, or the like. The reflective layer 24 of a metal compound,or a silicon oxide can be light transmissive. The reflective layer 24 isformed on the entirety or part of the embossed layer 23. The reflectivelayer 24 may be a single layer or multilayer. The multilayer can be thereflective layer 24 composed of two layers of a metal layer and a metalcompound or a silicon oxide. When the metal layer is partially formed inthe reflective layer 24, a region in which the metal layer is formed isselectively engraved to record two-dimensional information. Inparticular, the outer shape of the metal layer can be formed to havechromatic patterns or the like to improve anti-counterfeitingproperties.

The reflective layer 24 can be made of an inorganic compound other thanmetal. Inorganic compounds have a high refractive index and easilyincrease reflectance.

In production of the reflective layer 24 made of a metal, a metalcompound, or an inorganic compound, a vapor deposition method can beused.

The vapor deposition method may use evaporation, CVD or sputtering. Thereflective layer 24 preferably has a thickness in the range of 40 (nm)or more and 1000 (nm) or less. When the thickness is 40 (nm) or more,the outline of the demetallized section becomes clear during laserengraving. When the thickness is 1000 (nm) or less, the reflective layercan be prevented from cracking during laser engraving or the like. Thereflective layer 24 preferably has a reflectance in the range of 30(%)or more and 95(%) or less. When the reflectance of the reflective layer24 is 30(%) or more, sufficient reflection is obtained. On the otherhand, when the reflectance of the reflective layer 24 is greater than95(%), processing of the reflective layer 24 becomes difficult althoughsufficient image brightness is obtained.

The reflective layer 24 can also be formed by using ink that absorbslaser light. The ink may be an offset ink, a letterpress ink, a gravureink, or the like, depending on the printing method. Depending on thedifference in composition, a resin ink, an oil-based ink, or awater-based ink may be used. Furthermore, depending on the difference indrying method, the ink may be an oxidative polymerization ink, apenetrative drying ink, an evaporation drying ink, or an ultravioletcurable ink. In addition, functional ink whose color varies depending onthe illumination angle or observation angle can also be used. Such afunctional ink may be an optically variable ink, a color shift ink, or apearl ink.

The integrated three-dimensional display illustrated in FIGS. 2, 20A,and 20B is attached to the object 26. This attachment can be performedby thermal pressure transfer. In other words, processing for attachmentcan be thermal pressure transfer. The object 26 can be a print medium.The object 26 may be a bill, coupon, card, board, poster, tag, seal, orthe like. Cards, boards, and tags generally have a flat surface, andprovide good readability of codes, and a 3D image with reduceddistortion. The object 26 may be made of paper, polymer, or the like.Paper, polymer, or the like can be adhered via the adhesive layer 25.Further, in addition to paper and polymer, the material may also bemetals, ceramics, or other materials that can be adhered via theadhesive layer 25.

The adhesive layer 25 may be any material that can adhere the integratedthree-dimensional display 10 to the object 26, and can be apressure-sensitive adhesive with tackifier, thermoplastic adhesive, orthe like.

Further, when a surface of the integrated three-dimensional display 10is damaged by scratching or the like, the reconstructed image 40 may beblurred. Therefore, a protective layer (not shown) may be provided on asurface of the integrated three-dimensional display 10. The protectivelayer may also be provided with hard coating properties. The hardcoating properties may refer to the hardness in the range of H or moreand 5H or less in the pencil hardness test (JIS K5600-5-4). Thisprevents a surface of the integrated three-dimensional display 10 frombeing damaged by scratching or the like.

The integrated three-dimensional display 10 preferably has a surfacewith a gloss at 20° (Gs(20°)) in the range of 15 or more and 70 or lessWhen the gloss at 20° (Gs(20°)) is less than 15, non-glare propertiesbecome prominent, and the light converging point Sn cannot reconstruct agood image.

On the other hand, when the gloss at 20° (Gs(20°)) is greater than 70,non-glare properties become insufficient, and reflected light may appearin the reconstructed image 40, making it difficult to capture or observethe reconstructed image 40. More preferably, the gloss at 20° (Gs(20°))may be in the range of 20 or more and 60 or less.

The recording surface 14 may preferably have a transmitted image claritydefined by (C(0.125)+C(0.5)+C(1.0)+C(2.0)) of 200% or more. Furthermore,the recording surface 14 may have a haze (Hz) of 1.0% or more and 25% orless. Gloss at 20° was measured according to JIS-K7105-1981 by using agloss meter (micro-TRI-gloss, manufactured by BYK-Gardner). Transmittedimage clarity was measured according to JIS-K7105-1981 by using an imageclarity meter (product name: ICM-1DP, manufactured by Suga TestInstruments Co., Ltd.).

Light transmitted through the non-glare film can be calculated from amaximum wavelength M and a minimum wavelength m, which are measured bypermitting light to pass through a moving optical comb, based on aformula C=(M−m)/(M+m)×100. As the transmitted image clarity C (%)increases, the clearer and better the image obtained. Since opticalcombs of four different widths (0.125 (mm), 0.5 (mm), 1.0 (mm), and 2.0(mm)) were used for the measurement, 100%×4=400(%) will be the maximumvalue.

Haze (Hz) was measured according to JIS-K7105-1981 by using a haze meter(NDH2000, manufactured by Nippon Denshoku Industries, Co., Ltd.).

Total luminous reflectance can be measured according to JIS-K7105 byusing a spectrophotometer U-4100 manufactured by HitachiHigh-Technologies Corporation, and collecting total light with anintegrating sphere.

According to another embodiment of the integrated three-dimensionaldisplay 11 having the cross-sectional configuration shown in FIGS. 19Aand 19B, the release layer 27 may be omitted, and the recording surface14 may be directly laminated on the substrate 12. In this case, since norelease layer 27 is provided, the substrate 12 remains after attachmentto the object 26 via the adhesive layer 25.

When the substrate 12 forms a print layer, a matte paper sheet ispreferably used. Examples of the matte paper sheet include high qualitypaper, medium quality paper, matte coated paper, and art paper. Theprint layer can also be formed using an ink.

The ink may be pigment ink or dye ink. The pigment ink may be of organiccompound or inorganic compound. Inorganic pigments include graphite,cobalt, titanium, and the like. Organic pigments include phthalocyaninecompounds, azo pigments, organic complexes, and the like. Further,fluorescent or phophorescent pigment can also be used.

Furthermore, the print layer can also be formed by dispersing a pigmentin a polymer matrix, and printing. Examples of the polymer matrixinclude acrylic resin, urethane resin, and rosin. The additive amount ofthe pigment is preferably 0.1(%) or more and 10(%) or less. The dye inkmay be an organic dye ink.

Organic dyes include natural dyes and synthetic dyes. Synthetic dyesinclude azo dye, organic complex dye, and the like. Further, fluorescentor phophorescent dye may be used. The print layer can also be formed bydispersing a dye in a polymer matrix, and printing. Examples of thepolymer matrix include acrylic resin, urethane resin, and rosin. Theadditive amount of the dye is preferably 0.5% or more and 30% or less.

As described above, according to the integrated three-dimensionaldisplay to which a method of recording identification information of anembodiment of the present invention is applied, it is possible to reducecomputation time by a computer due to the calculated element regionbeing provided, reduce the noise of spatial information, and obtain aclear hologram.

In the calculation, in particular, the phase angle φ can be calculatedand recorded. Such a phase hologram can modulate only the phasecomponents of light while achieving high diffraction efficiency. Thus,light can be controlled while the brightness of light being kept high.

Further, computation time by a computer can be further reduced bylimiting the area for recording the phase angle φ within the overlaparea 19. In addition, the percentage of light illuminating theintegrated three-dimensional display 10 can also be controlled.

Still further, when a portion of the calculated element region 16 otherthan the phase angle recorded area 18 is defined as a phase anglenon-recorded area 20, the reconstructed image 40 reconstructed at thelight converging points Sn can have a brightness lower than that in acase where no phase angle non-recorded area 20 is provided by the amountrepresented by (phase angle recorded area 18)/(phase angle recorded area18+phase angle non-recorded area 20). Thus, the brightness of light canbe controlled.

Moreover, the three-dimensional reconstructed image 40 can bereconstructed only when the phase angle recorded area 18 is illuminatedwith light. That is, the larger the phase angle recorded area 18, thebrighter the reconstructed image 40, and the smaller the phase anglerecorded area 18, the darker the reconstructed image 40. Althoughcapable of reconstructing only a dark reconstructed image 40, the phaseangle non-recorded area 20 can be used as another optical element.

Furthermore, when the overlap area 19 is composed of one monochromaticregion 22, a monochromatic image can be three-dimensionallyreconstructed. When the overlap area 19 is composed of a plurality ofmonochromatic regions 22, a color image can be three-dimensionallyreconstructed.

When the two-dimensional information 50 is provided on the recordingsurface 14 to overlap at least part of the reconstructed image 40 in adepth direction of the recording surface 14, anti-counterfeitingproperties can be greatly enhanced.

Still further, when the two-dimensional information 50 is provided onthe recording surface 14, it can be positioned not to cover the entiresurface of the overlap area 19 to prevent the light converging point Snreconstructed from the overlap area 19 from disappearing.

At least one of the reconstructed image 40 and the two-dimensionalinformation 50 can be used as personal identification information.Alternatively, a dynamic three-dimensional reconstructed image 40 and anon-dynamic two-dimensional information 50 such as a character or a markcan be displayed in combination. Further, anti-counterfeiting propertiesof the two-dimensional information 50 can also be enhanced.

Moreover, one of a planar shape of the monochromatic region 22, thetwo-dimensional information 50, and the reconstructed image 40, acomposite thereof, or a combination thereof can represent amachine-readable code. The machine-readable code can be a QR code, abarcode, a data matrix, or the like. Accordingly, a variable code havingfurther enhanced anti-counterfeiting properties can be produced.

Further, when information other than a phase angle is recorded in thephase angle non-recorded area 20 in the calculated element region 16,information other than the phase components of light of thethree-dimensional reconstructed image 40, such as scattering,reflection, and diffraction properties of light, can be controlled bythe phase angle non-recorded area 20.

Furthermore, the phase angle can be converted into the depth of thepixel, and can be recorded in the overlap area 19.

Still further, the respective calculated element regions 16 positionedon the recording surface 14 without overlapping other calculated elementregions 16 can have different colors to thereby reconstruct a full-colorthree-dimensional reconstructed image 40. Further, when the recordingsurface 14 includes a metallic reflective layer 24, the reflectionefficiency of light can be improved so that a bright reconstructed image40 can be reconstructed.

The integrated three-dimensional display 10 and 11 can be attached tothe object 26. Furthermore, although the reconstructed image 40 isblurred and may not be clearly visible depending on the size and numberof illumination sources such as fluorescent lamps in a typical officeenvironment or the like, the reconstructed image 40 can be clearlyvisible when illuminated with an LED, which is a point light source, ora light source of a smartphone or a cash register reader.

Further, when the reflective layer 24 is made of a metal, the metal canbe demetallized by laser engraving to record a machine-readable code.Identification information can be recorded in this pattern. As thedemetallization amount increases, authentication of the machine-readablecode becomes easier, whereas the brightness of the three-dimensionalreconstructed image 40 decreases. Therefore, when 30(%) or more and70(%) or less of a metal of the portion of the metallic reflective layer24 that is desired to be non-reflective is demetallized, it is possibleto obtain both the ease of authentication of a code pattern andsufficient brightness for the reconstructed image 40.

As described above, according to the integrated three-dimensionaldisplay to which a method of recording identification information of anembodiment of the present invention is applied, a three-dimensionalimage that can be reconstructed in full-color without causingiridescence and is suitable for mass production, in combination with amachine-readable code, can be provided.

[First Modification]

A first modification of the present invention will be described. Thepresent embodiment can be combined with other embodiments.

In the following description, differences from the first embodiment ofthe present invention will be described.

In the first embodiment of the present invention described above, astamper is used to form the monochromatic region 22 having the pixeldepth T according to the phase angle. However, as another technique, asilver halide exposure material may be exposed and developed, and thenbleached, followed by modifying the developed silver into a silver saltsuch as silver halide to make the material transparent. Alternatively, athermoplastic or the like, whose refractive index or surfaceconfiguration changes due to light, may be used.

With this configuration as well, reflected light can converge on thelight converging points Sn to reconstruct a desired holographicreconstructed image 40, and, as described in the first embodiment, athree-dimensional image that can be reconstructed in full-color withoutcausing iridescence and is suitable for mass production, in combinationwith a machine-readable code, can be provided.

[Second Modification]

A second modification of the present invention will be described. Thepresent embodiment can be combined with other embodiments.

In the following description, differences from the first embodiment ofthe present invention will be described.

In the first embodiment of the present invention described above, inorder to reconstruct the holographic reconstructed image 40, the phaseangle φ calculated based on the phase component is recorded in thecorresponding pixel of the overlap area 19, and the depth T of the pixelg according to the phase angle φ is further recorded.

In the second modification of the present invention, in order toreconstruct the holographic reconstructed image 40, a void having a voidsize modulated according to the phase angle φ is embedded instead of thedepth T according to the phase angle φ being recorded in thecorresponding pixel g of the overlap area 19.

FIG. 24 is a cross-sectional view of an example in which a void having avoid size according to a phase angle is embedded in a pixel.

In this configuration, as shown in FIG. 24, a void having a void sizeaccording to the phase angle φ which is calculated at the coordinates ofeach pixel g is embedded in the pixel g constituting the monochromaticregion 22 in the overlap area 19.

FIG. 24 illustrates two monochromatic regions 22 (#1) and (#2), and someof the pixels g in the monochromatic region 22 (#1) include a void V1having a void size modulated according to the phase angle φ which iscalculated in the monochromatic region 22 (#1).

Similarly, some of the pixels g in the monochromatic region 22 (#2)include a void V2 having a void size modulated according to the phaseangle φ which is calculated in the monochromatic region 22 (#2).

With this configuration as well, reflected light can converges on thelight converging points Sn to reconstruct a desired holographicreconstructed image 40, and, as described in the first embodiment of thepresent invention, a three-dimensional image that can be reconstructedin full-color without causing iridescence and is suitable for massproduction, in combination with a machine-readable code, can beprovided.

The invention of the present application is not limited to theembodiments described above, and may be modified in various ways at thestage of implementation, without departing from the spirit of thepresent invention. The embodiments of the present invention may beadequately combined and implemented, and the combinations each haveadvantageous effects accordingly. Furthermore, the embodiments of thepresent invention described above include inventions of various stages.Therefore, a plurality of disclosed elements may be appropriatelycombined so that various inventions can be obtained.

What is claimed is:
 1. An integrated three-dimensional display,comprising: a recording surface on which information for reconstructinga hologram is recorded, wherein the recording surface includes acalculated element region in which phase components of light from lightconverging points of a holographic reconstructed image are calculated,the calculated element region being defined by one-to-one correspondenceto the light converging points, and a phase angle recorded area forrecording a phase angle calculated based on the phase components, thephase angle recorded area includes a plurality of monochromatic regionshaving a uneven structure surface in which protrusion structures andrecess structures are alternately arranged at a pitch that is anintegral multiple of a predetermined resolution, the phase angle isrecorded in an overlap area in which the calculated element region andthe phase angle recorded area overlap each other, and light converges onthe light converging points at specific distances from the recordingsurface, the specific distances being determined for the respectivelight converging points even when light reflected from the plurality ofmonochromatic regions converges.
 2. The integrated three-dimensionaldisplay of claim 1, wherein two-dimensional information is provided onthe recording surface to overlap at least part of the reconstructedimage in a depth direction of the recording surface.
 3. The integratedthree-dimensional display of claim 2, wherein the two-dimensionalinformation is provided on the recording surface and does not cover anentire surface of the phase angle recorded area.
 4. The integratedthree-dimensional display of claim 2, wherein at least one of thereconstructed image and the two-dimensional information includespersonal identification information.
 5. The integrated three-dimensionaldisplay of claim 2, wherein at least one of a shape of the monochromaticregions on the recording surface, a shape of the two-dimensionalinformation, and a shape of the reconstructed image represents acharacter or a mark.
 6. The integrated three-dimensional display ofclaim 2, wherein at least one of a shape of the monochromatic regions onthe recording surface, a shape of the two-dimensional information, and ashape of the reconstructed image represents a machine-readable code. 7.The integrated three-dimensional display of claim 1, wherein therecording surface further includes a phase angle non-recorded area thatdoes not record a phase angle, and the phase angle non-recorded area inthe calculated element region has a mirror surface.
 8. The integratedthree-dimensional display of claim 1, wherein the recording surfacefurther includes a phase angle non-recorded area that does not recordthe phase angle, and information other than the phase angle can berecorded in the phase angle non-recorded area in the calculated elementregion.
 9. The integrated three-dimensional display of claim 8, whereinthe information other than the phase angle is information including atleast one of scattering, reflection, and diffraction of light.
 10. Theintegrated three-dimensional display of claim 1, wherein the phase angleis calculated as φ according to the following formula: $\begin{matrix}{{{W( {{kx},{ky}} )} = {\sum\limits_{n = 0}^{N\;\max}{\sum\limits_{{ky} = {Y\;\min}}^{Y\;\max}{\sum\limits_{{kx} = {X\;\min}}^{X\;\max}{{amp} \cdot {\exp( {i\;\phi} )}}}}}}{\phi = {\frac{\pi}{\lambda \cdot {O_{n}(z)}}\{ {( {{O_{n}(x)} - {kx}} )^{2} + ( {{O_{n}(y)} - {ky}} )^{2}} \}}}} & \lbrack {{Math}.\mspace{11mu} 1} \rbrack\end{matrix}$ where (kx, ky) are coordinates of a pixel that constitutesthe monochromatic regions, W (kx, ky) represents the phase components ofthe coordinates (kx, ky), n is an index of the light converging pointsSn (n=0 to Nmax), amp is an amplitude of light at the light convergingpoints, i is an imaginary number, λ is a wavelength of light inreconstruction of the reconstructed image, On (x, y, z) representscoordinates of the light converging points, and Xmin, Xmax, Ymin, andYmax are coordinates indicating a range of the calculated element regiondefined for the respective light converging points.
 11. The integratedthree-dimensional display of claim 1, wherein a number of types of themonochromatic regions corresponds to a number of colors required toreconstruct the hologram, a color of reflected light reflected from themonochromatic regions is one of the colors required to reconstruct thehologram, a depth of the recess structures in each of the monochromaticregions is determined depending on the color of reflected light, and thedetermined depth of the recess structures is recorded in themonochromatic regions in the overlap area instead of the phase anglebeing recorded in the overlap area.
 12. The integrated three-dimensionaldisplay of claim 1, wherein a void is embedded in the overlap areainstead of the phase angle being recorded in the overlap area, the voidhaving a void size modulated according to the phase angle.
 13. Theintegrated three-dimensional display of claim 1, comprising a pluralityof the calculated element regions, wherein, among the plurality ofcalculated element regions, the respective calculated element regionspositioned on the recording surface without overlapping other calculatedelement regions are colored in different colors from other calculatedelement regions.
 14. The integrated three-dimensional display of claim1, wherein the recording surface includes a metallic reflective layer.15. The integrated three-dimensional display of claim 1, wherein theintegrated three-dimensional display is attached to an object.
 16. Theintegrated three-dimensional display of claim 1, wherein a distancebetween the recording surface and each of the light converging points isin a range of 0.5 (mm) or more and 50 (mm) or less, and the integratedthree-dimensional display is designed to be observed in an angular rangeof 0(°) or more and 70(°) or less relative to a direction normal to therecording surface.
 17. A method of recording identification informationcomprising demetallizing the metallic reflective layer corresponding toidentification information to thereby record the identificationinformation on the integrated three-dimensional display of claim
 14. 18.The method of recording identification information of claim 17, whereinthe identification information is a machine-readable code, and thedemetallizing includes demetallizing 30(%) or more and 70(%) or less ofa metal of a portion of the metallic reflective layer which is desiredto be non-reflective in order to produce the machine-readable code bycombining reflection and non-reflection.
 19. A method of recordingidentification information comprising: providing a print layer on therecording surface; and recording identification information on the printlayer to thereby record the identification information on the integratedthree-dimensional display of claim 1.